使用intent发送内容分享链接

1、使用intent发送一段白文本

mReportButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent i = new Intent(Intent.ACTION_SEND);
                i.setType("text/plain");
                i.putExtra(Intent.EXTRA_TEXT, getCrimeReport());
                i.putExtra(Intent.EXTRA_SUBJECT,
                        getString(R.string.crime_report_subject));
                i = Intent.createChooser(i, getString(R.string.send_report));
                startActivity(i);
            }
        });

触发后会出现一个应用选择器，如果设置了默认应用或者设备上只有一个activity可以响应隐式intent，选择器上可能只有一个应用。

2、从联系人中获取信息

final Intent pickContact = new Intent(Intent.ACTION_PICK,
                ContactsContract.Contacts.CONTENT_URI);
        pickContact.addCategory(Intent.CATEGORY_APP_BROWSER);
        mSuspectButton = (Button) view.findViewById(R.id.crime_suspect);
        mSuspectButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                startActivityForResult(pickContact, REQUEST_CONTACT);
            }
        });

请求的信息会封装到intent中在onActivityResult中获取

@Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode != Activity.RESULT_OK) {
            return;
        }
        if (requestCode == REQUEST_CONTACT && data != null) {
            Uri contactUri = data.getData();
            // Specify which fields you want your query to return
            // values for.
            String[] queryFields = new String[]{
                    ContactsContract.Contacts.DISPLAY_NAME
            };
            // Perform your query - the contactUri is like a "where"
            // clause here
            Cursor c = getActivity().getContentResolver()
                    .query(contactUri, queryFields, null, null, null);
            try {
                // Double-check that you actually got results
                if (c.getCount() == 0) {
                    return;
                }
                // Pull out the first column of the first row of data -
                // that is your suspect's name.
                c.moveToFirst();
                String suspect = c.getString(0);
                mCrime.setSuspect(suspect);
                mSuspectButton.setText(suspect);
            } finally {
                c.close();
            }
        }
    }

该solution中如果设备上没有联系人应用，本应用就会崩溃，通过

PackageManager packageManager = getActivity().getPackageManager();
        if (packageManager.resolveActivity(pickContact,
                PackageManager.MATCH_DEFAULT_ONLY) == null) {
            mSuspectButton.setEnabled(false);
        }

检查是否有能响应intent的app，如果没有就将button置灰。
PackageManager知道本设备包括了哪些组件。